JP2021075266A - Travel control device, method and program - Google Patents

Abstract

To provide a travel control device which quantitatively predicts a recovery amount of regenerative energy and uses the same in travel control.SOLUTION: A travel control device is mounted on a vehicle provided with an electric motor and an internal combustion engine as power sources. The travel control device comprises: a creation section which creates a velocity profile where velocities of the vehicle at respective times are predicted; an estimation section which approximates the velocity profile with a predetermined approximation model and estimates a prediction amount of regenerative energy, energy recoverable through regenerative braking of the electric motor, on the basis of an approximation result; and a determination section which determines the power source to be used for traveling on the basis of the predicted amount of the regenerative energy.SELECTED DRAWING: Figure 2

Description

The present invention relates to a traveling control device or the like mounted on a vehicle.

In a hybrid vehicle equipped with an electric motor and an internal combustion engine, it is possible to improve fuel efficiency by efficiently using the electric motor and the internal combustion engine for running control.

Patent Document 1 provides driving support for vehicles that guides the user to a braking start point at which regenerative braking operation needs to be started, based on the position of the vehicle and map information of a stop point or deceleration point required such as a railroad crossing or a curve. The device is disclosed. In this vehicle driving support device, it is possible to increase the amount of regenerative energy recovered by urging the user to operate the regenerative brake at a deceleration that enables efficient recovery of regenerative energy.

Japanese Patent No. 4702086

In the technique of Patent Document 1, it is possible to predict the point where the recovery of the regenerative energy can be expected, but the amount of the recovery of the regenerative energy cannot be predicted quantitatively. If the amount of regenerative energy recovered can be quantitatively predicted at an early stage, it may be used for suitable driving control.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a travel control device used for travel control by quantitatively predicting the amount of regenerated energy recovered.

In order to solve the above problems, one aspect of the present invention is a travel control device mounted on a vehicle equipped with an electric motor and an internal combustion engine as a power source, and creates a speed profile that predicts the speed of the vehicle at each time. The creation unit and the estimation unit that approximates the speed profile with a predetermined approximate model and estimates the estimated amount of regenerative energy, which is the energy that can be recovered by the regenerative braking of the motor, based on the approximation result, and the estimated amount of regenerative energy. Based on this, it is a travel control device including a determination unit that determines a power source used for travel.

According to the present invention, since a speed profile that predicts the speed of the vehicle is created, the recovery amount of regenerative energy can be quantitatively predicted based on the speed profile, and a travel control device that uses the predicted recovery amount for travel control is provided. can do.

The figure which shows the traveling control device which concerns on one Embodiment of this invention, and the functional block of the peripheral part thereof. The figure which shows the flowchart of the traveling control processing which concerns on one Embodiment of this invention. The figure which shows the example of the speed profile which concerns on one Embodiment of this invention. Diagram showing a graph of the Gaussian function The figure which shows a part of the example of the velocity profile which concerns on one Embodiment of this invention, and the graph which approximated this by a Gaussian function. The figure which shows the example of the velocity profile which concerns on one Embodiment of this invention, and the graph which approximated this Gaussian function. The figure which shows the graph of the example of the amount which is interlocked with the change of kinetic energy, and the amount which is dissipated by running resistance among the required power which concerns on one Embodiment of this invention. The figure which shows the graph of the example of the required power which concerns on one Embodiment of this invention. The figure which shows the graph of the example of the integrated value of the required power which concerns on one Embodiment of this invention.

(Embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The travel control device according to the present embodiment quantitatively predicts the amount of regenerated energy recovered at an early stage by using a speed profile that predicts the speed of the vehicle, and performs suitable travel control for improving fuel efficiency.

<Structure>
FIG. 1 shows the travel control device 10 according to the present embodiment and the functional blocks of the peripheral portion thereof. The travel control device 10 is mounted on the vehicle. Other vehicles include an internal combustion engine ECU 20, an internal combustion engine 21, a transmission 22, an electric motor ECU 30, an electric motor 31, a battery ECU 40, a battery 41, a manager ECU 50, a driving support ECU 60, an automatic driving ECU 65, a storage unit 70, and a communication unit 80. The travel control ECU 90, the EPS ECU 100, the EPS device 101, the brake ECU 110, and the brake device 111 are included.

Vehicles may also include various devices such as accelerator pedal sensors, brake pedal sensors, cameras and obstacle sensors, vehicle speed sensors, yaw rate sensors, GPS sensors, and navigation systems, but the illustrations are omitted. To do.

The internal combustion engine 21 and the electric motor 31 are actuators that serve as a power source for driving the vehicle. The electric motor 31 is also a generator that generates electric power and a braking device that generates braking force by regenerative braking.

The internal combustion engine ECU 20 controls the internal combustion engine 21 and the transmission 22 that changes the rotation speed between the input and the output to generate a driving torque or a braking torque by the engine brake. It is an ECU (Electric Control Unit) to perform.

The electric motor ECU 30 is an ECU that controls the electric motor 31 to generate a driving torque and a braking torque by a regenerative brake.

The battery 41 supplies electric power to the electric motor 31 and other devices by electric discharge, and charges the electric power (recovered energy) obtained by regenerative braking of the electric motor 31. The battery ECU 40 is an ECU that controls the charging and discharging of electric power of the battery 41.

The travel control ECU 90 is an ECU that controls the internal combustion engine ECU 20 and the motor ECU 30 according to the travel mode described later.

The EPS (electric power steering) device 101 is an actuator that performs steering by changing the steering angle of the wheels to change the traveling direction of the vehicle. The EPS ECU 100 is an ECU that controls the EPS device 101.

The brake device 111 (foot brake device) is an actuator that generates a braking force by a frictional force against a member that rotates with the wheels. The brake ECU 110 is an ECU that controls the brake device 111.

The driving support ECU 60 is an ECU that executes driving support functions such as collision avoidance, following a vehicle in front, and maintaining a lane. The driving support ECU 60 outputs instructions for controlling the movement of the vehicle, such as acceleration / deceleration and steering angle, based on information acquired from various sensors and the like. The function and number of the driving support ECU 60 are not limited.

The automatic driving ECU 65 outputs instructions for controlling the movement of the vehicle, such as acceleration / deceleration and steering angle, in order to execute the automatic driving function based on the information acquired from various sensors and the like.

The manager ECU 50 gives instructions to the travel control ECU 90, the EPS ECU 100, the brake ECU 110, etc. (hereinafter collectively referred to as an actuator ECU) based on the instructions from the operation support ECU 60, the automatic operation ECU 65, and the like. For example, the acceleration instruction is given to the traveling control ECU 90, the steering instruction is given to the EPS ECU 100, and the deceleration instruction is given to the traveling control ECU 90 and the brake ECU 110.

When the manager ECU 50 receives instructions from a plurality of driving support ECUs 60 and the like, the manager ECU 50 performs a process called arbitration, which determines which instruction to control the vehicle, based on a predetermined rule, and the actuator ECU 50 is based on the arbitration result. Give instructions to. The operation content of the user's steering wheel, brake pedal, accelerator pedal, etc. may be acquired by the manager ECU 50 and subject to arbitration processing by the manager ECU 50, or acquired by the actuator ECU, and the actuator ECU is manually operated by the user. The operation and the instruction from the manager ECU 50 may be arbitrated individually.

The storage unit 70 stores one or more travel histories of the user. The traveling history is information including the speed of the vehicle at each time point in the driving period when the vehicle has been driven in the past. The storage unit 70 generates a traveling history by periodically storing the speed of the vehicle acquired from a vehicle speed sensor or the like provided in the vehicle while the vehicle is in the power-on state, for example. The storage unit 70 may be provided, for example, as part of a car navigation system.

The communication unit 80 can wirelessly communicate with a server outside the vehicle, another vehicle, or the like, and can receive a travel history other than the user obtained based on the travel results of the other vehicle.

The travel control device 10 is an ECU including a creation unit 11, an estimation unit 12, and a determination unit 13. The creation unit 11 creates a speed profile based on the travel history. The estimation unit 12 estimates the estimated amount of regenerative energy, which is the energy that can be recovered by regenerative braking, based on the velocity profile. The determination unit 13 determines which of the electric motor 31 and the internal combustion engine 21 to be used for traveling based on the expected amount of regenerative energy.

Each of the above ECUs is typically a computer provided with a memory and a processor. The processor of each ECU realizes a function by reading and executing a program stored in a non-temporary memory, for example. These ECUs are connected to each other by a communication line, and can operate cooperatively by appropriately communicating with each other.

The configuration of the vehicle-mounted device and the configuration of the travel control device 10 described above are examples, and can be added, replaced, changed, or omitted as appropriate. Further, the functions of each device can be appropriately integrated into one device or distributed to a plurality of devices for implementation.

For example, the travel control device 10 may be provided as an independent ECU, may be provided as a part of the manager ECU 50 or the travel control ECU 90, or the like, and the function of the travel control device 10 may be provided as the manager ECU 50, the travel control ECU 90, or the like. It may be distributed in the above.

Further, for example, the travel control device 10, the operation support ECU 60, the automatic operation ECU 65, the manager ECU 50, the travel control ECU 90, and the like may be provided as one ECU. Further, for example, the automatic operation ECU 65 may not be provided.

<Processing>
The details of the processing according to the present embodiment will be described below. FIG. 2 is a flowchart of processing executed by the travel control device 10. This process is started, for example, when the user powers on the vehicle and starts a trip, and is executed until the user turns the vehicle into a power-off state and ends the trip.

(Step S101): The creation unit 11 creates a speed profile. The speed profile is information that represents the speed of the vehicle at each point in time expected during this trip.

FIG. 3 shows an example of a speed profile. In FIG. 3, the horizontal axis represents the elapsed time from the start of the trip, and the vertical axis represents the speed of the vehicle. As an example, the speed change pattern used in the fuel consumption rate test (JC08 mode) established in Japan. The speed profile based on is shown. The velocity profile graph generally contains a plurality of peaks, indicating that acceleration and deceleration are repeated during one trip.

The creation unit 11 can create a speed profile based on, for example, the travel history stored in the storage unit 70. In a simple example, if the user's driving pattern is only a pattern of traveling on the same route at the same time zone on weekdays for commuting, it is considered that the pattern of the time-dependent change in speed included in the traveling history is substantially the same. In such a case, the creation unit 11 may create a speed profile based on any of the past travel histories.

Further, the storage unit 70 associates the travel history with attributes such as the day of the week and the time zone of travel, classifies and stores them, and the creation unit 11 matches the attributes such as the day of the week and the time zone of this trip. A speed profile may be created based on a large number of travel histories. As a result, even if the user does not have one running pattern, if the running patterns are common to each attribute, the running pattern can be specified with a certain accuracy and the speed profile can be created with high accuracy.

Further, the storage unit 70 acquires a travel route from a navigation system or the like provided in the vehicle, includes it in the travel history, and stores it, and the creation unit 11 stores the travel history having a high degree of similarity to the travel route of this trip. You may create a speed profile based on. This method can be executed when the user can acquire the travel route set by the creation unit 11 by setting the travel route in the navigation system or the like in this trip, but the accuracy of the speed profile can be improved. Can be improved.

If a travel route is set for this trip, the creation unit 11 inquires the server of road traffic information such as the speed limit and congestion forecast along the travel route via the communication unit 80. A speed profile may be created based on this, or a server capable of creating a speed profile based on road traffic information along a travel route is requested to create a speed profile via the communication unit 80. , You may get the created speed profile.

The creation unit 11 may acquire a travel history other than the user via the communication unit 80 and create a speed profile based on the travel history. The server collects, classifies, and stores the travel history associated with, for example, the day of the week, the time zone, the travel route, etc. from a large number of vehicles, and the creation unit 11 inquires of the server to perform this trip. A running history with a high degree of matching of classification may be acquired, and a speed profile may be obtained based on this.

In addition, the server divides a plurality of people into groups and stores the travel history of each person, and the creation unit 11 creates a speed profile based on the travel history selected from the same group as the user. May be good. For example, if people in the same area at home and at work are grouped in the same group, the accuracy of the speed profile when traveling for commuting can be improved.

Alternatively, the creation unit 11 acquires the travel history stored by the vehicle from one or more other vehicles instead of the server via the communication unit 80, and based on this, the speed profile as described above. May be created.

In each of the above methods, when there are a plurality of running histories that are candidates for the speed profile, for example, the creation unit 11 may use any one of them as the speed profile, and the average of these may be used as the speed. It may be a profile. The method for creating the speed profile is not limited, and the above methods may be combined as appropriate. Further, the speed profile may be created using only one of the driving history of the user and the traveling history other than the user, or the speed profile may be created using both of them.

(Step S102): The estimation unit 12 approximates the velocity profile with a predetermined approximation model. In this embodiment, the sum of Gaussian functions is used for approximation. FIG. 4 shows a graph (t ≧ 0) of a Gaussian function represented by (Equation 1) with time t as a variable. Here, μ is the peak position (time), v _max is the peak value, and σ is a parameter that defines the spread of the distribution.

_{FIG. 5 shows a graph in which the parameters μ, v max} , and σ are suitably defined in (Equation 1), and the speed change in the 0 ≦ t ≦ 100 (seconds) portion of the speed profile shown in FIG. 3 is approximated. In FIG. 5, the velocity profile is shown by a dotted line, and the approximate graph is shown by a solid line.

The method of calculating the parameters μ, v _max , and σ from the velocity profile is not limited, but the amount of calculation increases when the least squares method or the like is used. Here, an example of a suitable calculation method capable of reducing the amount of calculation will be described. As shown in FIG. 5, when the start time at which the speed represented by the speed profile becomes greater than 0 is T0 and the stop time at which the speed returns to 0 is T1, this method is the speed in the section from time T0 to time T1. The profile is approximated by a Gaussian function in which this interval is in the range μ ± 3σ. That is, in this method, assuming that the length of the period of the interval is T', the parameter σ can be calculated by (Equation 2).

Further, for the average velocity _vav in this section, (Equation 3) holds based on this approximation.

Therefore, the parameter v _max can be calculated by (Equation 4). In (Equation 4), D is the mileage in this section.

Further, the parameter μ can be calculated by (Equation 5).

In this way, when the speed of one section where the speed of the speed profile is positive is approximated by the Gaussian function, the parameters μ, v _max , and σ are the running start time, the average speed _{vav of the vehicle, and running in that section.} It can be calculated by the distance D or the travel time T'. In calculating the parameters, the average speed _vav and the required travel time T'based on the actual value may be used, the mileage D and the required travel time T'based on the actual value may be used, or the actual value is used. The mileage D and the average speed _vav may be used. According to this calculation method, the parameters of the Gaussian function can be calculated with a small amount of calculation by a simple calculation, and the processing load can be suppressed.

In the present embodiment, the entire speed profile, having different peak positions mu _i, is approximated by the sum of the corresponding Gaussian function in each section as described above. Each Gaussian function can have different peak values v _maxi and distribution spread σ _i . Assuming that the number of Gaussian functions used is N _{, the approximate expression can be expressed as (Equation 6) with μ i} , v _maxi , and σ _i (i = 1, 2, ..., N) as parameters.

Here, the parameters μ _i , v _maxi , and σ _i (i = 1, 2, ..., N) can be calculated by using the above-mentioned calculation method. Alternatively, these parameters can be derived using other known fitting techniques. For example, the integral value S obtained by integrating the absolute value of the difference between the velocity value V (t) of the velocity profile and the approximate value v (t) over the entire period (0 ≦ t ≦ T) of the velocity profile is minimized. You can also set parameters. The integrated value S is represented by (Equation 7).

By this method, the parameters μ _i , v _maxi , σ _i (i = 1, 2, ..., N) of (Equation 6) were derived, and the velocity change of the velocity profile shown in FIG. 3 was approximated over the entire period. The graph is shown in FIG. In FIG. 6, the velocity profile is shown by a dotted line, and the approximate graph is shown by a solid line. In this example, N = 10.

As shown in FIG. 6, it can be seen that a good approximation is obtained that characterizes the velocity change in one trip. The value of N is not limited and may be determined according to the length of the trip period of the speed profile and the number of peaks in the speed change. For example, in the case of a trip of about 1200 seconds, N = 10 is a sufficiently good approximation. Is obtained, and a better approximation is obtained at N = 20. When the trip period is relatively short or the number of peaks is relatively small, N = 1 may be set.

(Step S103): The estimation unit 12 estimates the expected amount of regenerative energy, which is the energy obtained by the regenerative braking of the electric motor 31, using the approximate model. The estimation method will be described below.

First, the estimation unit 12 derives the required power P (t), which is the power to be given to the vehicle in order to maintain the speed v (t). P (t) is expressed as (Equation 8).

Here, m is the weight of the vehicle. m · dv (t) / dt represents the rate of change in the momentum of the vehicle, and a · (v (t)) ² + b · v (t) + c represents the running resistance. The required power P (t) is the sum of these multiplied by the vehicle speed v (t). That is, the required power P (t) is the sum of the power that contributes to the change in the kinetic energy of the vehicle and the power that is dissipated by the running resistance, and is necessary to realize the speed v (t) at time t. It is the power that is said to be. As shown in (Equation 8), the running resistance can be suitably approximated by expressing the sum of the component proportional to the square of the speed, the component proportional to the square, and the constant component.

In FIG. 7, time is taken on the horizontal axis and power (power) is taken on the vertical axis. Of the required power P (t) in the 0 ≦ t ≦ 100 (seconds) portion of the speed profile shown in FIG. An example of the amount that contributes to the change in kinetic energy (the first term on the right side of the equation 8) is shown by a solid line, and an example of the amount that is dissipated by the running resistance (the second term on the right side of the equation 8) is shown by a dotted line.

Further, FIG. 8 shows a graph of the total amount of required power P (t), with time on the horizontal axis and power (power) on the vertical axis.

Next, the estimation unit 12 estimates the period during which the regenerative energy can be recovered and the expected recovery amount based on the required power P (t). In the graph shown in FIG. 8, the period (t1 <t <t2) in which the value of the required power P (t) is negative is the period in which the regenerative energy is expected to be recovered. Further, the integrated value of the magnitude of the required power during this period shown in (Equation 9), that is, the area of the region shown by hatching in FIG. 8 is an estimated value E of the expected amount of regenerative energy to be recovered.

FIG. 9 shows a graph of the integrated value I (t) of the required power shown in FIG. 8 from time 0 to t, with time on the horizontal axis and energy on the vertical axis. I (t) is represented by (Equation 10).

In FIG. 9, the difference between the energy value at the peak and the energy value when the graph becomes flat after the peak is equal to the estimated value E of the expected amount of regenerative energy to be recovered.

By extracting one or more periods in which the required power is negative over the entire period of the velocity profile and obtaining the integral value of the required power magnitude for each period, the regenerative energy is recovered at the start of the trip. It is possible to estimate one or more possible periods and the expected recovery amount for each period.

The weight m of the vehicle, the coefficients a, b, and c are all constants basically determined by the characteristics of the vehicle, and if appropriate values are set, good estimation accuracy can be obtained, but the required power can be obtained. If one or more variable factors that can affect the effect can be obtained, the weight m, the coefficients a, b, and c can be further estimated by making the following corrections based on the obtained variable factors. The accuracy can be improved.

For example, when the estimation unit 12 can acquire the load weight of the occupants, luggage, etc. by input from the weight sensor or the like provided in the vehicle or the user, the weight m is obtained by adding the load weight to the weight of the vehicle itself to the weight m of the vehicle. It may be corrected.

Further, when the estimation unit 12 can acquire the fluctuation factors of the running resistance such as the type of the road surface, the slope of the road surface, and the weather, the coefficients a, b, and c may be corrected by these factors.

For example, when a traveling route is set for this trip, the type of the road surface and the slope of the road surface can be specified, and the coefficient can be corrected by using this information. Information on the type of road surface and the slope of the road surface may be stored in advance in the storage unit 70 in association with the map information, or may be acquired by the communication unit 80 from an external server or the like. In addition, the coefficient can be corrected using the weather. The weather may be acquired by various sensors provided in the vehicle, or may be acquired by the communication unit 80 from an external server or the like.

For example, when the road surface is relatively slippery such as a gravel road, the running resistance is corrected to be larger than when the road surface is a paved road which is relatively difficult to slip.

In addition, when the slope of the road surface indicates that it is an uphill road, it is corrected so that the running resistance becomes larger than when it is a flat road, and when it indicates that it is a downhill road, it is a flat road. Correct so that the running resistance is smaller than that. In (Equation 8), the influence of the increase / decrease in the potential energy of the vehicle on the required power P (t) is reflected by the correction of the traveling resistance based on the slope of the road surface.

In addition, when the weather is rain or snow, the running resistance is corrected to be larger than when it is sunny. Further, when the traveling route is set for this trip, the traveling direction of the vehicle can be estimated, so that the traveling resistance may be corrected based on the air volume and the wind direction as the weather. For example, when the air volume is not 0, the traveling resistance is corrected to be larger if it is a head wind and smaller if it is a tail wind, depending on the air volume and the wind direction.

When correcting such running resistance, specifically, the values of the coefficients a, b, and c are changed. In this case, the coefficients a, b, and c will change depending on the position of the vehicle, but a, b, and c are each reduced to a function of time t via the approximate expression of (Equation 6). be able to. In consideration of the speed-dependent characteristic of the influence of the fluctuation factor on the running resistance, it is possible to appropriately determine which of the coefficients a, b, and c should be corrected and to what extent.

Further, the estimation unit 12 may make a correction to the value of the estimated value E in place of the above-mentioned correction, or in addition to the above-mentioned correction, according to the above-mentioned fluctuation factors. That is, the correction coefficient α (for example, 0 ≦ α ≦ 1) is set for each period so that the value of the corrected estimated value E becomes smaller as the load weight becomes larger or the running resistance becomes larger due to fluctuation factors. The correction may be performed as in the formula 11).

The correction coefficient α may reflect the efficiency of regenerative braking so that the higher the efficiency of regenerative braking, the larger the estimated value E after correction. The efficiency of regenerative braking can be derived, for example, based on the rotation speed of the motor 31 assumed according to the speed v (t) and the efficiency map corresponding to the rotation speed.

The specific numerical calculation method for the above processing is not limited, and a known calculation algorithm can be appropriately used. In the present embodiment, the characteristics of the velocity profile can be expressed with relatively few parameters by the approximation using the Gaussian function, so that the amount of calculation can be suppressed. In addition, prepare the function values of the Gauss function and its derivatives for multiple numerical values and the constant integral value of the Gauss function in multiple numerical ranges in advance as a numerical table, and use it for calculation by referring to the numerical table as appropriate. For example, the amount of calculation can be further reduced.

(Step S104): The determination unit 13 determines whether or not the condition for traveling using the electric motor 31 is satisfied. In the present embodiment, as an example, the determination unit 13 is between the electric motor 31 and the internal combustion engine 21 between the electric motor mode in which only the electric motor 31 is used and the internal combustion engine mode in which only the internal combustion engine 21 is used. Controls to switch the driving mode.

Here, the determination unit 13 appropriately acquires various information from various sensors provided in the vehicle, the driving support ECU 60, the manager ECU 50, and the like, and makes a determination as follows as an example.

(1) When the intention to decelerate the vehicle is satisfied, it is determined whether the following conditions (1-1) to (1-3) are satisfied. It should be noted that the intention of decelerating the vehicle is satisfied, for example, at least one of the fact that the user has operated the brake pedal and the user has released the accelerator pedal operation while the vehicle is running. Alternatively, while the driving support function of the driving support ECU 60 or the automatic driving function of the automatic driving ECU 65 is operating, an instruction indicating deceleration or stop is given from these ECUs.

(1-1) The speed of the vehicle is equal to or higher than the first speed threshold.
If the actual speed of the current vehicle is relatively low, sufficient rotation speed of the motor 31 cannot be obtained during regenerative braking, and efficient recovery of regenerative energy cannot be expected. Therefore, it is determined whether or not the speed of the vehicle is equal to or higher than the first speed threshold value defined as the speed at which a certain degree of regeneration efficiency can be expected.

(1-2) The required power is equal to or less than the first power threshold.
When the current required power is relatively large, even if the internal combustion engine 21 can output the required power, the motor 31 may not be able to output the required power because the maximum output is generally smaller than that of the internal combustion engine 21. Therefore, it is determined whether or not the required power is equal to or less than the first power threshold value defined as the power that can be output by the motor 31.

(1-3) The storage rate of the battery 41 is equal to or lower than the first storage rate threshold.
When the current storage rate of the battery 41 is high, the amount of electric power that can be charged is further small, and there is a possibility that all the regenerative energy cannot be stored. Therefore, it is determined whether or not the storage rate of the battery 41 is equal to or less than the first storage rate threshold value defined as the storage rate capable of charging a sufficient amount of electric power. The amount of electricity stored may be used instead of the electricity storage rate for the determination.

If all the determination results of (1-1) to (1-3) are affirmative, the process proceeds to step S105, and in other cases, the process proceeds to step S106.

(2) Except for cases other than the above-mentioned (1), that is, when the intention to decelerate the vehicle is satisfied, it is determined whether the following conditions (2-1) to (2-4) are satisfied.

(2-1) The speed of the vehicle is less than the second speed threshold.
If the actual speed of the current vehicle is relatively high, the internal combustion engine 21 is generally more efficient than the motor 31. Therefore, it is determined whether or not the speed of the vehicle is less than the second speed threshold value defined as the speed at which the motor 31 can be expected to be more efficient. The second speed threshold is a speed higher than the first speed threshold.

(2-2) The required power is equal to or less than the first power threshold.
For the same reason as in (1-2) above, it is determined whether or not the required power is equal to or less than the first power threshold value defined as the power that can be output by the motor 31.

(2-3) The total of the energy for the motor currently stored in the vehicle and the expected amount of recovered energy in the period in which the regenerative energy can be recovered is equal to or higher than the first energy threshold value.
If the total amount of stored electricity that the vehicle currently stores in the battery 41 and can be supplied to the motor 31 and the expected amount of power that can be recovered in the next period when the regenerative energy can be recovered is relatively small, the motor 31 When traveling with the battery 41, the amount of electricity stored in the battery 41 decreases, which may interfere with each function of the vehicle. Therefore, it is determined whether or not the total amount is equal to or greater than the first energy threshold value defined as a sufficient amount.

(2-4) Currently, the vehicle is running using the internal combustion engine 21, and the first time threshold value or more has elapsed since the operation of the internal combustion engine 21 was started.
If the operation of the internal combustion engine 21 is stopped immediately after the operation is started, the user may feel that the internal combustion engine 21 is malfunctioning or the vehicle behavior is unstable, which may cause discomfort or anxiety. Therefore, it is determined whether or not the first time threshold value or more, which is set as a sufficient elapsed time that does not cause discomfort even if the operation of the internal combustion engine 21 is stopped after the operation of the internal combustion engine 21 is started, has elapsed.

If all the determination results of (2-1) to (2-4) are affirmative, the process proceeds to step S105, and in other cases, the process proceeds to step S106.

(Step S105): The determination unit 13 determines the traveling mode to the motor mode. In the present embodiment, the determination unit 13 notifies the travel control ECU 90 that the travel mode is set to the motor mode. The travel control ECU 90 causes the motor ECU 30 to control travel by the motor 31.

In the motor mode, regenerative braking is performed and the kinetic energy of the vehicle is recovered as electric power. If the user depresses the brake pedal a lot, or the driving support ECU 60 gives a high-priority sudden deceleration instruction to avoid a collision, etc., and a certain level of deceleration is required, sufficient braking force is applied. In order to generate the brakes, the manager ECU 50 and the brake ECU 110 control the brake device 111 to generate the braking force.

(Step S106): The determination unit 13 determines the traveling mode to the internal combustion engine mode. In the present embodiment, the determination unit 13 notifies the travel control ECU 90 that the travel mode is the internal combustion engine mode. The travel control ECU 90 causes the internal combustion engine ECU 20 to control travel by the internal combustion engine 21.

(Step S107): The creating unit 11 determines whether or not the condition for updating the expected amount of regenerative energy is satisfied. The condition to be updated is, for example, that the degree of agreement between the time-dependent change in speed in actual running up to the present and the speed profile created in step S101 is lower than a predetermined allowable value. The degree of agreement can be derived by using a known method as appropriate. For example, the degree of agreement can be derived based on the integral value of the absolute value of the difference between the velocity value of the velocity profile and the actual velocity value over a certain period of time. If the degree of agreement is lower than the permissible value, it is considered that the accuracy of the period during which the regenerative energy can be recovered and the expected amount are also low. If the condition for updating is satisfied, the process proceeds to step S108, and if not, the process proceeds to step S104.

(Step S108): The estimation unit 12 updates these by re-estimating the period during which the regenerative energy can be recovered and the expected amount. The updating method is not particularly limited, but for example, the estimation unit 12 performs deformation by compressing or expanding the time scale of the speed profile so as to have a high degree of agreement with the time-dependent change of the speed in the actual running up to the present, and after the deformation. The update can be performed by performing the same processing as in steps S102 and S103 based on the speed profile of.

Alternatively, the creation unit 11 performs the same processing as in step S101, selects a travel history other than the travel history used to create the current speed profile, and newly creates a speed profile based on this. The estimation unit 12 may update by performing the same processing as in steps S102 and S103 based on the newly created speed profile. For example, when the vehicle stops, it is considered that a new trip is started from that place at that time, and the travel history may be selected in the same manner as in step S101.

Further, since the value of the above-mentioned variable factor may have changed in such an update, the latest value may be used for correction. By performing such an update, it is possible to improve the estimation accuracy of the period during which the regenerative energy can be recovered and the estimated amount. After the processing of this step, the process proceeds to step S104.

In the above processing, two driving modes are set: an electric motor mode in which the vehicle travels using only the motor 31 and an internal combustion engine mode in which the vehicle travels using only the internal combustion engine 21. When the amount of regenerative energy recovered can be expected to be large as in the above condition (2-3), the opportunity to drive using the electric motor 31 is increased and the fuel efficiency is improved as compared with the case where the amount of regenerative energy is expected to be small. can do. Focusing on this, switching control between any two driving modes among the three driving modes of the motor mode, the internal combustion engine mode, and the hybrid mode in which the motor 31 and the internal combustion engine 21 are used together, and 3 The expected recovery amount of regenerated energy can also be used to improve fuel efficiency in switching control between two driving modes.

For example, if the amount of regenerative energy recovered can be expected to be large, the opportunity to transition from the internal combustion engine mode to the hybrid mode is increased, or the opportunity to transition from the hybrid mode to the motor mode is increased compared to the case where the amount of regenerative energy is expected to be small. You can increase it.

<Effect>
The travel control device 10 according to the present embodiment can quantitatively predict the amount of regenerated energy recovered at an early stage by using a speed profile that predicts the speed of the vehicle. Utilizing this predicted result, suitable running control becomes possible. That is, when the amount of regenerative energy recovered can be expected to be large, the chances of traveling by using the electric motor 31 can be increased and the fuel efficiency can be improved as compared with the case where the amount of regenerative energy is expected to be small.

The travel control device 10 suppresses the number of parameters for calculating the expected recovery amount of regenerative energy by approximating the speed profile with a Gaussian function, and also refers to a numerical table related to the Gaussian function prepared in advance. The amount of calculation can be suppressed.

Since the travel control device 10 can create a speed profile based on the user and the travel history other than the user, the expected recovery amount of the regenerative energy can be estimated even if the user does not set the travel route. Further, when the user has set a traveling route, a speed profile can be created by using the traveling route, and the estimation accuracy can be improved.

Since the travel control device 10 corrects the expected amount based on the fluctuation factor that is considered to affect the recovery amount of the regenerative energy, the estimation accuracy can be improved by reflecting the fluctuation factor.

When the degree of agreement between the speed profile and the time-dependent change in the actual speed of the vehicle is low, the travel control device 10 re-estimates the expected recovery amount, so that the estimation accuracy can be improved.

When determining the traveling mode, the traveling control device 10 determines which of the internal combustion engine 21 and the electric motor 31 is suitable, not only the expected recovery amount of the regenerative energy, but also the storage rate of the battery 41, the speed of the vehicle, and the required power. Since the determination is made in consideration of the regenerative energy storage possibility, the operating efficiency, and the feasibility of the required power based on the above, the reliability and stability of the vehicle control can be improved.

Although one embodiment of the present invention has been described above, the present invention can be appropriately modified and implemented. INDUSTRIAL APPLICABILITY The present invention includes a travel control method executed by a travel control device including a processor and a memory as well as a travel control device, a travel control program, a computer-readable non-temporary storage medium that stores the travel control program, and travel. It can be regarded as a vehicle equipped with a control device.

The present invention is useful for a traveling control device mounted on a vehicle or the like.

10 Travel control device 11 Creation unit 12 Estimating unit 13 Determining unit 20 Internal combustion engine ECU
21 Internal combustion engine 22 Transmission 30 Motor ECU
31 Motor 40 Battery ECU
41 Battery 50 Manager ECU
60 Driving support ECU
65 Automatic operation ECU
70 Storage unit 80 Communication unit 90 Travel control ECU
100 EPS ECU
101 EPS device 110 Brake ECU
111 Brake device

Claims (12)

A travel control device mounted on a vehicle equipped with an electric motor and an internal combustion engine as a power source.
A creation unit that creates a speed profile that predicts the speed of the vehicle at each time,
An estimation unit that approximates the velocity profile with a predetermined approximation model and estimates the estimated amount of regenerative energy, which is the energy that can be recovered by the regenerative braking of the motor, based on the approximation result.
A travel control device including a determination unit that determines the power source used for travel based on the expected amount of regenerative energy. The travel control device according to claim 1, wherein the creation unit creates the speed profile based on either or both of the travel history of the user and the travel history of a non-user. The travel control device according to claim 1 or 2, wherein the predetermined approximation model uses a model that approximates the time course of the vehicle speed represented by the speed profile by the sum of Gaussian functions having different peak positions. The travel control device according to claim 3, wherein the estimation unit calculates a parameter of the Gaussian function using at least any two of a vehicle speed, a mileage, and a travel time. Based on the approximation result, the estimation unit derives a power represented by the sum of the power that contributes to the change in the kinetic energy of the vehicle and the power that is dissipated by the running resistance. The above period is defined as a period during which the regenerative energy can be recovered, and the time-integrated value of the magnitude of the power in the period is used as an estimated value of the expected amount of the regenerative energy in the period. 4. The travel control device according to 4. The travel control device according to claim 5, wherein the estimation unit further estimates the expected amount of the regenerative energy based on one or more fluctuation factors. The travel control device according to claim 6, wherein the variable factor is at least one of the type of road surface, the slope of the road surface, the load weight of the vehicle, and the weather. The travel control device according to claim 6 or 7, wherein the estimation unit corrects the power based on the fluctuation factor. The travel control device according to any one of claims 6 to 8, wherein the estimation unit corrects the time integration value based on the fluctuation factor. When the condition including the total of the energy for the motor currently stored in the vehicle and the expected amount of the regenerative energy in the next period is equal to or more than the threshold value, the determination unit sets the motor. The travel control device according to any one of claims 5 to 9, wherein the travel control device is determined to be used for traveling. It is a travel control method executed by a travel control device mounted on a vehicle equipped with an electric motor and an internal combustion engine as a power source.
Steps to create a speed profile that predicts the speed of the vehicle at each time,
A step of approximating the velocity profile with a predetermined approximation model and estimating the expected amount of regenerative energy, which is the energy that can be recovered by the regenerative braking of the motor, based on the approximation result.
A traveling control method including a step of determining the power source to be used for traveling based on the expected amount of regenerative energy. A travel control program that is executed by a computer of a travel control device mounted on a vehicle equipped with an electric motor and an internal combustion engine as a power source.
Steps to create a speed profile that predicts the speed of the vehicle at each time,
A step of approximating the velocity profile with a predetermined approximation model and estimating the expected amount of regenerative energy, which is the energy that can be recovered by the regenerative braking of the motor, based on the approximation result.
A travel control program comprising a step of determining the power source to be used for travel based on the expected amount of regenerative energy.

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